[QUOTE=alcor;42249]It’s the first time I’ve ever heard of a 14" line going from the Diverter Line to the Poorbuoy Degasser (MGS). Normal rig practice is to use the Diverter line for overboard emergency direction of gas and fluid, and to choose the downwind side. These lines are always sited underneath the rig in order to ensure gas is exported away from the rig.
Whose responsibility is it to line up? It’s TO equipment. I’d like to see their updated procedure on use of this ‘extra’ line.
Why is the line there? Probably used for controlling gas in the Riser when gains are seen. I’ve heard they also had a choke on this line in order to avoid evacuating all of the contents of the Riser as the gas expands. Remember, the Slip Joint Packer would only be able to hold back 500 psi max pressure. The use of this line may have been useful from an environmental point of view where no SOBM ends up over the side.
Would the rig have exploded if the Diverter Line had been lined up correctly and the Diverter Sealed? Possibly! But, that’s what those lines are there for…to avoid gas engulfing the rig. In this case, gas swamped the whole of the rig.
I think TO have some issues to clarify on this subject. They’ll probably say it was a BP directive. But, who is in charge of the vessel? Whose responsibility is it to protect the vessel, and what are the steps we take to ensure this is performed. There are Emergency Procedures in place on every vessel. TO will reveal their’s during the trials, if a report doesn’t come out sonner highlighting the dilemma in this type of situation.
One thing is for sure, when you install an extra line, you need to know where you’re diverting.[/QUOTE]
You have thrown back at me another “xx number of questions”. I don’t intend to answer them and add further speculation.
[B]However,… what I believe needs highlighting to all of us is the divertor procedures/practices and piping arrangements on the newer generation rigs (and maybe others also?).
“With the divertor closed, they have the facility to ALSO direct flow/fluids back to the low pressure/low volume poor-boy degasser (MGS) and thereafter onto the shakers/pits etc!”
The idea behind this is to be able to minimise the amount of mud contamination that goes out to the sea!. Yes, it’s backwards thinking… but I guess we have to blame the environmentalist? thinking within our combined ranks.[/B]
As for your questions, I will give a few clarifications…
“[B][I]It’s the first time I’ve ever heard of a 14” line going from the Diverter Line to the Poorbuoy Degasser (MGS).[/I][/B]"
It’s a common setup/practise/SOP on newer build rigs and maybe others?.
“[I][B]Whose responsibility is it to line up? It’s TO equipment. I’d like to see their updated procedure on use of this ‘extra’ line.[/B][/I]”
Responsibility is with both the operator (oil company) and the rig owner to agree (and document) a procedure.
Normally?, there are several documents set up before hand to “bridge” the differences between operator (oil company) and rig owner procedures. They are normally called bridging documents and designed to state/clarify whose procedure will be used when there is a conflict between each procedure.
" [I][B]‘Why is the line there?’[/B][/I] [I]Probably used for controlling gas in the Riser when gains are seen[/I]."
Modern thinking. See above re the environmentalists.
[B][I]“I’ve heard they also had a choke on this line in order to avoid evacuating all of the contents of the Riser as the gas expands.” [/I][/B]
Ouch!!! A low pressure system trying to be controlled? No further comment on their wisdom or thinking behind this.
[B][I]“The use of this line may have been useful from an environmental point of view where no SOBM ends up over the side.”[/I][/B]
See above comments.
[I][B]“Would the rig have exploded if the Diverter Line had been lined up correctly and the Diverter Sealed? Possibly![/B][/I] [I]But, that’s what those lines are there for…to avoid gas engulfing the rig. In this case, gas swamped the whole of the rig.”[/I]
That’s the million dollar question!.
You say the rig may have [I][B]possibly[/B][/I] exploded if diverting was done (correctly? and in whose opinion?) overboard.
It’s very hypothetical. We just don’t know.
However, I do believe that the risk of explosion would have been less (by going o/board) than by “pumping mud and gas back onto the areas of the rig.”
As for the remaining questions… a carefull review of what and how we do things would be prudent.